270 Energy and transport for thefuture
It is interesting to see how the energy we consume is used.^4 Tak-
ing the world average for commercial energy (i.e. omitting ‘traditional
energy’), about twenty-two per cent of primary energy is used in trans-
portation, about forty-one per cent by industry, about thirty-four per
cent in buildings (two-thirds in residential buildings and one-third in
commercial buildings) and about three per cent in agriculture. It is also
perhaps interesting to know how much energy is used in the form of
electricity. Rather more than one-third of primary energy goes to make
electricity at an average efficiency of conversion of about one-third. Of
this electrical power about half, on average, is utilised by industry and
the other half in commercial activities and in homes.
How much is spent on energy? Taking the world as a whole, the
amount spent per year by the average person for the 1.7 toe of energy
used, is about five per cent of annual income. Despite the very large
disparity in incomes, the proportion spent on primary energy is much
the same in developed countries and developing ones.
How about energy for the future? If we continue to generate most
of our energy from coal, oil and gas, do we have enough to keep us
going? Current knowledge of proven recoverable reserves (Figure 11.2)
indicates that known reserves of fossil fuel will meet demand for the
period up to 2020 and substantially beyond. Before mid century, if de-
mandcontinues to expand, oil and gas production will come under in-
creasing pressure. Further exploration will be stimulated, which will
lead to the exploitation of more sources, although increased difficulty
of extraction can be expected to lead to a rise in price. So far as coal is
concerned, there are operating mines with resources for production for
well over a hundred years.
Estimates have also been made of the ultimately recoverable fossil
fuel reserves, defined as those potentially recoverable assuming high but
notprohibitive prices and no significant bans on exploitation. Although
these are bound to be somewhat speculative,^5 they show that, at current
rates of use, reserves of oil and gas are likely to be available for l00
years and of coal for more than l000 years. In addition to fossil fuel
reserves considered now to be potentially recoverable there are reserves
not included in Figure 11.2, such as the methane hydrates, which are
probably very large in quantity but from which extraction would be
much more difficult.
Likely reserves of uranium for nuclear power stations should also be
included in this list. Whenconverted to the same units (assuming their
use in ‘fast’ reactors) they are believed to be at least 3000 and possibly as
high as 12 000 Gtoe, substantially greater than likely fossil fuel reserves.
For at least the twenty-first century, sufficient fossil fuels in total are
available to meet likely energy demand. It is considerations other than